Such sieve devices are sufficiently known from the state of the art and serve to remove, for example, coarse material to be sieved (wood, stones, etc.) from sewage flowing in a sewer. To achieve this, the sieve device is generally integrated into the sewer in such a way that the sieve surface extends perpendicularly or slightly inclined upwards, starting from the sewer bottom. To allow the discharge of the material to be sieved that has been held back by the screen forming the sieve surface, the latter extends most of the time above the maximum expected water level.
The rotating operation of the cleaning rake (from which more than one can be provided as well) causes the material to be sieved to be finally conveyed along the sieve surface and upwards towards a discharge, where it is removed from the cleaning rake with the help of a scraper, for example.
One difficulty encountered when building the corresponding devices (hereinafter also named “rakes”) is to position the cleaning rake in such a way that when it passes the sieve surface it moves as parallel as possible to the longitudinal direction of the grate bars to prevent a tilting of the cleaning rake. Owing to existing production tolerances, however, this cannot always be achieved without problems.